Preparation method and preparation equipment of nuclear-grade graphite

Abstract

The invention relates to a preparation method of nuclear-grade graphite. The preparation method comprises the following steps: S1, mixing and kneading, S2, crushing, S3, isostatic pressing, S4, roasting, S5, dipping, S6, graphitizing and S7, purifying. Nuclear-grade graphite preparation equipment comprises a roasting furnace and a purification furnace, the roasting furnace comprises a sealed graphitization cavity, the front end and the rear end of the graphitization cavity are provided with a sealed feeding cavity and a sealed discharging cavity respectively, and the end of the feeding cavity and the end of the discharging cavity are each provided with an openable end sealing door; openable middle sealing doors are arranged between the graphitization cavity and the feeding cavity and between the graphitization cavity and the discharging cavity, backflow assemblies are arranged between the feeding cavity and the graphitization cavity and between the discharging cavity and the graphitization cavity, and each backflow assembly comprises a backflow pipe and a first sucking pump. The invention aims to solve or at least alleviate the defects in the prior art, and provides the nuclear-grade graphite preparation method and preparation equipment, purification is carried out in the graphite roasting and purification process, and the method is simple and easy to operate, and is very suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of graphite production, and in particular to a method and equipment for preparing nuclear-grade graphite. Background Art

[0002] With the development of the national economy, the contradiction between energy supply and demand in my country is prominent. Nuclear energy has little environmental pollution and low demand for energy materials. It is an effective means to solve my country's energy problem. Because of its low thermal expansion coefficient, excellent thermal shock resistance and low neutron activation performance, graphite is an excellent neutron deceleration material for nuclear reactors. Its deceleration ratio is second only to heavy water, but it is low in cost and allows natural uranium to be utilized. Nuclear graphite is a polycrystalline material with a high degree of graphitization and high purity to improve the effective utilization rate of fission neutrons, and it has isotropy so that the material has stability in three-dimensional space under high-dose neutron radiation conditions. The prior art is to purify graphite with an inert gas at a temperature of about 2200°C to about 2600°C. So that graphite does not have an ash content of more than 300ppm or a boron equivalent of 2ppm. The boron equivalent of graphite (also known as "equivalent boron content") describes the neutron absorption ability of all impurities (calculated according to the type and amount of each impurity) and is recorded according to the ability of equivalent boron to absorb neutrons. Boron equivalent can be calculated using the method specified in ASTM C1233. However, such post-graphitization purification is very expensive. In addition, the purification process can only be used for surface treatment, and may not be effective for the internal purification of some already formed graphite blocks. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art, solve or at least alleviate the deficiencies of the prior art, and provide a method and equipment for preparing nuclear-grade graphite, which is simple and easy to operate and very suitable for large-scale production.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for preparing nuclear-grade graphite, the method comprising the following steps:

[0006] S1, kneading, putting high-purity calcined asphalt coke, high softening point modified asphalt, and low quinoline insoluble modified medium-temperature asphalt into a kneader at a weight ratio of 1: (0.18-0.28): 0.3 for kneading to obtain a kneaded product;

[0007] S2, crushing, crushing the kneaded material obtained in step S1 to obtain kneaded particles with a particle size not greater than 30 μm;

[0008] S3, isostatic pressing, the kneaded particles obtained in step S2 are placed in a rubber mold sleeve, and after compaction, vacuum is drawn with a vacuum degree of no more than 0.01 MPa, the rubber mold sleeve is sealed, and the rubber mold sleeve is placed in an isostatic press for molding to obtain a green embryo;

[0009] S4, roasting, placing the green embryo obtained in step S3 into a roasting furnace for roasting;

[0010] S5, impregnation, placing the product obtained in step S4 into an impregnation device and impregnating it with asphalt liquid;

[0011] S6, graphitization, placing the product obtained in step S5 into a graphitization furnace for graphitization, wherein the graphitization furnace is filled with inert gas during the graphitization process, and the pressure in the graphitization furnace fluctuates back and forth between 0.075 MPa and 0.3 MPa;

[0012] S7, purification, putting the product obtained in step S6 into a purification furnace for purification, during the purification process, the purification furnace is filled with inert gas and gradually filled with Freon, and the pressure in the purification furnace fluctuates back and forth between 0.01MPa and 0.3MPa to obtain nuclear grade graphite.

[0013] In order to further realize the present invention, the following technical solutions may be preferably selected:

[0014] Preferably, the particle size of the high-purity calcined asphalt coke in step S1 is 15-25 μm;

[0015] The high-purity calcined asphalt coke is crushed to 5-10 μm, and an organic solvent is used as a medium liquid phase dispersion mixing process to make the binder asphalt evenly coated on the surface of the aggregate carbon particles.

[0016] Preferably, step S4 and step S5 are repeated several times in a cycle.

[0017] A nuclear-grade graphite preparation device, the nuclear-grade graphite preparation device is used in a nuclear-grade graphite preparation method, the nuclear-grade graphite preparation device comprises a graphitization furnace and a purification furnace, the graphitization furnace comprises a sealed graphitization chamber, the front and rear ends of the graphitization chamber are respectively provided with a sealed feed chamber and a discharge chamber, the ends of the feed chamber and the discharge chamber are both provided with openable end sealing doors, and the graphitization chamber and the feed chamber and the discharge chamber are both provided with openable middle sealing doors;

[0018] A reflux assembly is provided between the feed chamber and the discharge chamber and the graphitization chamber, and the reflux assembly includes a reflux pipe and a first air pump. One end of the reflux pipe is connected to the graphitization chamber, and the other end is connected to the feed chamber or the discharge chamber. The first air pump is provided on the reflux pipe, and the first air pump pumps the gas in the feed chamber or the discharge chamber into the graphitization chamber. The reflux pipe is provided with a one-way valve, and the flow direction of the one-way valve is from the feed chamber or the discharge chamber to the graphitization chamber.

[0019] In order to further realize the present invention, the following technical solutions may be preferably selected:

[0020] Preferably, the graphitization furnace further comprises a heating chamber and a gas storage chamber which are sequentially arranged outside the graphitization chamber from the inside to the outside, a heating device is arranged in the heating chamber, and the gas storage chamber is connected to the graphitization chamber.

[0021] Preferably, one end of the reflux pipe is connected to the gas storage chamber, and the other end is connected to the feed chamber or the discharge chamber, the first air pump is arranged at a section of the reflux pipe close to the gas storage chamber, the reflux pipe is provided with an exhaust pipe between the first air pump and the feed chamber or the discharge chamber, one end of the exhaust pipe is connected to the reflux pipe, and the other end is connected to the air;

[0022] A section of the exhaust pipe and the reflux pipe close to the feed chamber or the discharge chamber is provided with a one-way valve and a valve in series.

[0023] Preferably, the purification furnace is provided with openings in the middle of both front and rear ends, and an openable outer closed door is provided at the opening. An adjustment plate is longitudinally slidably provided in the upper part of the purification furnace, and the periphery of the adjustment plate is sealed and slidably fitted with the inner wall of the purification furnace. The adjustment plate divides the internal space of the purification furnace into a purification chamber at the bottom and a pressurized chamber at the top;

[0024] A connecting pipe is arranged between the purification furnace and the graphitization furnace. The connecting pipe is a three-way pipe, and the three ends of the connecting pipe are respectively connected to the top of the purification furnace, the top of the pressurizing chamber and the bottom of the purification chamber.

[0025] Preferably, a gas filling device is provided outside the purification furnace, and the gas filling device is connected with the purification chamber and slowly injects Freon into the purification chamber.

[0026] Preferably, a gas filling bin is provided on the upper part of the adjustment plate, and the upper and lower ends of the gas filling bin are respectively connected to the pressurization chamber and the purification chamber, and a slide plate is provided in the gas filling bin for longitudinal sliding, and the periphery of the slide plate is sealed and slidably fitted with the inner wall of the gas filling bin, and the lower part of the gas filling bin is connected to the gas filling device.

[0027] Preferably, a baffle is provided at the connection between the gas filling bin and the purification chamber, a spring is provided between the baffle and the adjustment plate, and the spring drives the baffle to fit against the adjustment plate.

[0028] Preferably, a section of the connecting pipe close to the pressurizing chamber is provided with a valve, and a section of the connecting pipe close to the purification chamber is provided with a valve and a second vacuum pump in series.

[0029] Through the above technical solution, the beneficial effects of the present invention are:

[0030] The preparation method of the present invention introduces Freon gas into an inert gas environment during the purification process, which is conducive to the in-depth purification of the nuclear graphite block and greatly reduces impurities. During graphitization, the pressure in the graphitization furnace fluctuates back and forth between 0.075MPa and 0.3MPa. During the purification process, the pressure in the purification furnace fluctuates back and forth between 0.01MPa and 0.3MPa, which is more conducive to the volatilization of impurities along the holes generated in the graphite block during the roasting process, thereby ensuring the purification effect, and can effectively increase the density of graphite and reduce the thermal expansion coefficient of graphite. The present invention has a simple process, convenient operation, and less production equipment, thereby further reducing costs, facilitating promotion and application, and being suitable for large-scale production.

[0031] The preparation equipment of the present invention connects the graphitization furnace and the purification furnace, which is not only convenient for continuous production, but also realizes the recycling of inert gas through the first vacuum pump and the second vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the preparation equipment of the present invention;

[0033] Figure 2 A top view of the preparation device of the present invention;

[0034] Figure 3 For the present invention Figure 2 Sectional view at AA in the middle;

[0035] Figure 4 For the present invention Figure 2 Sectional view at the middle BB;

[0036] Among them: 1-graphitization chamber; 2-feeding chamber; 3-discharging chamber; 4-end sealing door; 5-middle sealing door; 6-reflux pipe; 7-heating chamber; 8-gas storage chamber; 9-purification furnace; 10-outer closed door; 11-adjusting plate; 13-connecting pipe; 14-purification chamber; 15-pressurizing chamber; 16-gas filling device; 17-gas filling bin; 18-slide plate; 19-baffle. DETAILED DESCRIPTION

[0037] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The following will be combined with the drawings in the embodiments of the invention to clearly and completely describe the technical solutions in the embodiments of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0039] Embodiment 1:

[0040] A method for preparing nuclear-grade graphite, the method comprising the following steps:

[0041] S1, kneading, putting high-purity calcined asphalt coke, high softening point modified asphalt, and low quinoline insoluble modified medium-temperature asphalt into a kneader at a weight ratio of 1: (0.18-0.28): 0.3 for kneading to obtain a kneaded product;

[0042] S2, crushing, crushing the kneaded material obtained in step S1 to obtain kneaded particles with a particle size not greater than 30 μm;

[0043] S3, isostatic pressing, the kneaded particles obtained in step S2 are placed in a rubber mold sleeve, and after compaction, vacuum is drawn with a vacuum degree of no more than 0.01 MPa, the rubber mold sleeve is sealed, and the rubber mold sleeve is placed in an isostatic press for molding to obtain a green embryo;

[0044] S4, roasting, placing the green embryo obtained in step S3 into a roasting furnace for roasting;

[0045] S5, impregnation, placing the product obtained in step S4 into an impregnation device and impregnating it with asphalt liquid;

[0046] S6, graphitization, placing the product obtained in step S5 into a graphitization furnace for graphitization, wherein the graphitization furnace is filled with inert gas during the graphitization process, and the pressure in the graphitization furnace fluctuates back and forth between 0.075 MPa and 0.3 MPa;

[0047] S7, purification, putting the product obtained in step S6 into a purification furnace for purification, during the purification process, the purification furnace is filled with inert gas and gradually filled with Freon, and the pressure in the purification furnace fluctuates back and forth between 0.01MPa and 0.3MPa to obtain nuclear grade graphite.

[0048] The particle size of the high-purity calcined pitch coke in step S1 is 15-25 μm;

[0049] The high-purity calcined asphalt coke is crushed to 5-10 μm, and an organic solvent is used as a medium liquid phase dispersion mixing process to make the binder asphalt evenly coated on the surface of the aggregate carbon particles.

[0050] The steps S4 and S5 are repeated several times in a cycle.

[0051] The preparation method of the present invention introduces Freon gas into an inert gas environment during the purification process, which is conducive to the in-depth purification of the nuclear graphite block and greatly reduces impurities. During graphitization, the pressure in the roasting furnace fluctuates back and forth between 0.075MPa and 0.3MPa. During the purification process, the pressure in the purification furnace fluctuates back and forth between 0.01MPa and 0.3MPa, which is more conducive to the volatilization of impurities along the holes generated in the graphite block during the roasting process, thereby ensuring the purification effect, and can effectively increase the density of graphite and reduce the thermal expansion coefficient of graphite. The present invention has a simple process, convenient operation, and less production equipment, thereby further reducing costs, facilitating promotion and application, and being suitable for large-scale production.

[0052] The relevant product testing data are as follows:

[0053]

[0054] Among them, ordinary isostatic graphite is graphite prepared by ordinary isostatic pressing process on the market, sample one graphite is prepared by introducing Freon gas during purification, sample two graphite is prepared by introducing Freon gas during purification and the pressure fluctuates back and forth between 0.075MPa and 0.3MPa during graphitization, sample three graphite is prepared by introducing Freon gas during purification and the purification pressure fluctuates back and forth between 0.01MPa and 0.3MPa, and sample four graphite is graphite prepared according to the method of Example 1.

[0055] Embodiment 2:

[0056] A nuclear-grade graphite preparation device, the nuclear-grade graphite preparation device is used in a nuclear-grade graphite preparation method, the nuclear-grade graphite preparation device comprises a graphitization furnace and a purification furnace, the graphitization furnace comprises a sealed graphitization chamber 1, the front and rear ends of the graphitization chamber 1 are respectively provided with a sealed feed chamber 2 and a discharge chamber 3, the ends of the feed chamber 2 and the discharge chamber 3 are both provided with an openable end sealing door 4, and the graphitization chamber 1 and the feed chamber 2 and the discharge chamber 3 are both provided with an openable middle sealing door 5;

[0057] A reflux assembly is provided between the feed chamber 2 and the discharge chamber 3 and the graphitization chamber 1, and the reflux assembly includes a reflux pipe 6 and a first air pump. One end of the reflux pipe 6 is connected to the graphitization chamber 1, and the other end is connected to the feed chamber 2 or the discharge chamber 3. The first air pump is arranged on the reflux pipe 6, and the first air pump draws the gas in the feed chamber 2 or the discharge chamber 3 into the graphitization chamber 1. The reflux pipe 6 is provided with a one-way valve, and the flow direction of the one-way valve is from the feed chamber 2 or the discharge chamber 3 to the graphitization chamber 1.

[0058] In order to optimize the product structure, the graphitization furnace also includes a heating chamber 7 and a gas storage chamber 8 which are arranged on the outside of the graphitization chamber 1 from the inside to the outside. A heating device is provided in the heating chamber 7, and the gas storage chamber 8 is connected to the graphitization chamber 1.

[0059] In order to achieve pressure fluctuation of the green embryo during roasting, one end of the reflux pipe 6 is connected to the gas storage chamber 8, and the other end is connected to the feed chamber 2 or the discharge chamber 3. The first vacuum pump is arranged at a section of the reflux pipe 6 close to the gas storage chamber 8. The reflux pipe 6 is provided with an exhaust pipe between the first vacuum pump and the feed chamber 2 or the discharge chamber 3. One end of the exhaust pipe is connected to the reflux pipe 6, and the other end is connected to the air.

[0060] The exhaust pipe and the reflux pipe 6 are both provided with a one-way valve and a valve in series at a section close to the feed chamber 2 or the discharge chamber 3 .

[0061] In order to achieve the pressure fluctuation during purification, the purification furnace 9 is provided with openings in the middle of both ends, and an openable outer closed door 10 is provided at the opening. An adjustment plate 11 is provided in the upper part of the purification furnace 9 for longitudinal sliding. The periphery of the adjustment plate 11 is sealed and slidably fitted with the inner wall of the purification furnace 9. The adjustment plate 11 divides the internal space of the purification furnace 9 into a purification chamber 14 at the bottom and a pressurized chamber 15 at the top.

[0062] A connecting pipe 13 is provided between the purification furnace 9 and the graphitization furnace. The connecting pipe 13 is a three-way pipe. The three ends of the connecting pipe 13 are respectively connected to the top of the purification furnace 9, the top of the pressurizing chamber 15 and the bottom of the purification chamber 14.

[0063] In order to add Freon gas during the purification process, a gas filling device 16 is provided outside the purification furnace 9 , and the gas filling device 16 is connected to the purification chamber 14 and slowly injects Freon into the purification chamber 14 .

[0064] In order to optimize the product structure, in this embodiment, a gas filling bin 17 is provided on the upper part of the adjustment plate 11, and the upper and lower ends of the gas filling bin 17 are respectively connected to the pressurization chamber 15 and the purification chamber 14, and a slide plate 18 is longitudinally slidably arranged in the gas filling bin 17. The periphery of the slide plate 18 is sealed and slidably fitted with the inner wall of the gas filling bin 17, and the lower part of the gas filling bin 17 is connected to the gas filling device 16.

[0065] In order to prevent the Freon gas from entering the purification chamber 14 when the Freon gas is injected into the gas filling chamber 17, a baffle 19 is provided at the connection between the gas filling chamber 17 and the purification chamber 14, and a spring is provided between the baffle 19 and the adjustment plate 1, and the spring drives the baffle 19 to fit the adjustment plate 1.

[0066] To further optimize the product structure, a section of the connecting pipe 13 close to the pressurizing chamber 15 is provided with a valve, and a section of the connecting pipe 13 close to the purification chamber 14 is provided with a valve and a second vacuum pump in series.

[0067] Example 3: Method of using Example 2

[0068] 1. The graphitization chamber 1, the feeding chamber 2 and the discharging chamber 3 are all in a sealed state first, the end sealing door 4 of the feeding chamber 2 is opened, the green embryo is transported to the feeding chamber 2 and the end sealing door 4 of the feeding chamber 2 is closed, and the air in the feeding chamber 2 is discharged by the first vacuum pump;

[0069] 2. Open the middle sealing door 5 between the feeding chamber 2 and the graphitization chamber 1, and transport the green embryo to the graphitization chamber 1 for heating. At this time, the inert gas in the graphitization chamber 1 enters the feeding chamber 2, so that the pressure in the graphitization chamber 1 is reduced;

[0070] 3. Close the middle sealing door 5 between the feeding chamber 2 and the graphitization chamber 1, and then use the first vacuum pump to pump the inert gas in the feeding chamber 2 to the graphitization chamber 1 to increase the pressure in the graphitization chamber 1;

[0071] 4. After the graphitization is completed, the middle sealing door 5 between the graphitization chamber 1 and the discharge chamber 3 is opened to transport the graphitized embryo to the discharge chamber 3. At this time, the pressure in the graphitization chamber 1 decreases, and then the middle sealing door 5 is closed. Then, the inert gas in the discharge chamber 3 is pumped into the graphitization chamber 1 by the first vacuum pump, and the pressure in the graphitization chamber 1 increases;

[0072] 5. Open the end sealing door 4 of the discharge chamber 3, transport the graphitized embryo body to the purification furnace 9, then close the end sealing door 4 of the discharge chamber 3, and exhaust the air in the discharge chamber 3 through the first vacuum pump;

[0073] 6. During the purification process, the inert gas in the purification chamber 14 is pumped into the graphitization chamber 1 by the second vacuum pump, so that the pressure in the purification chamber 14 is reduced and the pressure in the graphitization chamber 1 is increased. After a period of time, the inert gas in the graphitization chamber 1 flows back into the purification chamber 14, so that the pressure in the purification chamber 14 is increased and the pressure in the graphitization chamber 1 is reduced, and the above steps are repeated continuously; when the inert gas in the feed chamber 2 or the discharge chamber 3 is pumped into the graphitization chamber 1, the graphitization chamber 1 is connected with the pressurizing chamber 8 and the pressures in both are increased, the adjustment plate 11 and the slide plate 18 are both moved downward, and the Freon gas in the gas filling bin 17 is injected into the purification chamber 14, and at the same time, the space of the purification chamber 14 is reduced, so that the pressure in the purification chamber 14 is further increased.

[0074] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing nuclear-grade graphite, characterized in that: The preparation method comprises the following steps: S1. kneading: putting high-purity calcined asphalt coke, high softening point modified asphalt, and low quinoline insoluble modified medium-temperature asphalt into a kneader at a weight ratio of 1: (0.18-0.28): 0.3 to obtain a kneaded product; S2, crushing, crushing the mixture obtained in step S1 to obtain kneaded particles with a particle size not greater than 30 μm; S3, isostatic pressing, the kneaded particles obtained in step S2 are placed in a rubber mold sleeve, and after compaction, vacuum is drawn with a vacuum degree of no more than 0.01 MPa, the rubber mold sleeve is sealed, and the rubber mold sleeve is placed in an isostatic press for molding to obtain a green embryo; S4, roasting, placing the green embryo obtained in step S3 into a roasting furnace for roasting; S5, impregnation, placing the product obtained in step S4 into an impregnation device and impregnating it with asphalt liquid; S6, graphitization, placing the product obtained in step S5 into a graphitization furnace for graphitization, wherein the graphitization furnace is filled with inert gas during the graphitization process, and the pressure in the graphitization furnace fluctuates back and forth between 0.075 MPa and 0.3 MPa; S7, purification, putting the product obtained in step S6 into a purification furnace for purification, during the purification process, the purification furnace is filled with inert gas and gradually filled with Freon, and the pressure in the purification furnace fluctuates back and forth between 0.01MPa and 0.3MPa to obtain nuclear grade graphite.

2. A method for preparing nuclear-grade graphite according to claim 1, characterized in that: The particle size of the high-purity calcined pitch coke in step S1 is 15-25 μm; The high-purity calcined asphalt coke is crushed to 5-10 μm, and an organic solvent is used as a medium liquid phase dispersion mixing process to make the binder asphalt evenly coated on the surface of the aggregate carbon particles.

3. A nuclear-grade graphite preparation device according to claim 1, characterized in that: The steps S4 and S5 are repeated several times in a cycle.

4. A nuclear-grade graphite preparation device, which is used in a nuclear-grade graphite preparation method as claimed in any one of claims 1 to 3, and the nuclear-grade graphite preparation device comprises a graphitization furnace and a purification furnace, characterized in that: The graphitization furnace comprises a sealed graphitization chamber (1), wherein the front and rear ends of the graphitization chamber (1) are respectively provided with a sealed feed chamber (2) and a discharge chamber (3), the ends of the feed chamber (2) and the discharge chamber (3) are both provided with openable end sealing doors (4), and between the graphitization chamber (1) and the feed chamber (2) and the discharge chamber (3) are both provided with openable middle sealing doors (5); A reflux component is provided between the feed chamber (2) and the discharge chamber (3) and the graphitization chamber (1), the reflux component comprising a reflux pipe (6) and a first air pump, one end of the reflux pipe (6) being connected to the graphitization chamber (1) and the other end being connected to the feed chamber (2) or the discharge chamber (3), the first air pump being provided on the reflux pipe (6), and the first air pump pumping gas in the feed chamber (2) or the discharge chamber (3) into the graphitization chamber (1), the reflux pipe (6) being provided with a one-way valve, the flow direction of the one-way valve being from the feed chamber (2) or the discharge chamber (3) to the graphitization chamber (1).

5. A nuclear-grade graphite preparation device according to claim 4, characterized in that: The graphitization furnace further comprises a heating chamber (7) and a gas storage chamber (8) which are arranged in sequence from the inside to the outside on the outside of the graphitization chamber (1); a heating device is provided in the heating chamber (7); and the gas storage chamber (8) is connected to the graphitization chamber (1).

6. A nuclear-grade graphite preparation device according to claim 4, characterized in that: One end of the reflux pipe (6) is connected to the gas storage chamber (8), and the other end is connected to the feed chamber (2) or the discharge chamber (3); the first air pump is arranged at a section of the reflux pipe (6) close to the gas storage chamber (8); an exhaust pipe is arranged between the reflux pipe (6) and the feed chamber (2) or the discharge chamber (3); one end of the exhaust pipe is connected to the reflux pipe (6), and the other end is connected to the air; A section of the exhaust pipe and the return pipe (6) close to the feed chamber (2) or the discharge chamber (3) is provided with a one-way valve and a valve in series.

7. The nuclear-grade graphite preparation equipment according to claim 5, characterized in that: The purification furnace (9) is provided with an opening in the middle of both front and rear ends, and an openable outer closed door (10) is provided at the opening. An adjustment plate (11) is longitudinally slidably provided in the upper part of the purification furnace (9). The periphery of the adjustment plate (11) is sealingly slidably fitted with the inner wall of the purification furnace (9). The adjustment plate (11) divides the internal space of the purification furnace (9) into a purification chamber (14) at the bottom and a pressurizing chamber (15) at the top. A connecting pipe (13) is provided between the purification furnace (9) and the graphitization furnace. The connecting pipe (13) is a three-way pipe. The three ends of the connecting pipe (13) are respectively connected to the top of the purification furnace (9), the top of the pressure chamber (15) and the bottom of the purification chamber (14).

8. The nuclear-grade graphite preparation equipment according to claim 7, characterized in that: An aeration device (16) is provided outside the purification furnace (9), and the aeration device (16) is connected to the purification chamber (14) and slowly injects freon into the purification chamber (14).

9. The nuclear-grade graphite preparation equipment according to claim 8, characterized in that: A gas filling chamber (17) is arranged on the upper part of the regulating plate (11), and the upper and lower ends of the gas filling chamber (17) are respectively connected to the pressurizing chamber (15) and the purification chamber (14). A slide plate (18) is arranged in the gas filling chamber (17) for longitudinal sliding. The periphery of the slide plate (18) is sealed and slidably fitted with the inner wall of the gas filling chamber (17), and the lower part of the gas filling chamber (17) is connected to the gas filling device (16).

10. The nuclear-grade graphite preparation equipment according to claim 9, characterized in that: A baffle (19) is provided at the connection point between the gas filling bin (17) and the purification chamber (14), and a spring is provided between the baffle (19) and the adjustment plate (1), and the spring drives the baffle (19) to fit against the adjustment plate (1).

11. A nuclear-grade graphite preparation device according to claim 10, characterized in that: A section of the connecting pipe (13) close to the pressurizing chamber (15) is provided with a valve, and a section of the connecting pipe (13) close to the purification chamber (14) is provided with a valve and a second vacuum pump in series.

Images